Boscovich, Ruggero GiuseppeSerbo-Croatian Rudjer Josip Bošković ( born May 18, 1711 , Ragusa, Dalmatia [now Dubrovnik, Croatia]—died Feb. 13, 1787 , Milan [Italy] ) astronomer and mathematician who gave the first geometric procedure for determining the equator of a rotating planet from three observations of a surface feature and for computing the orbit of a planet from three observations of its position.

Boscovich’s father was a Croat (some sources say Serb) and his mother was Italian. He entered the Society of Jesus (Jesuits) in 1726 and studied mathematics and physics at the Collegium Romanum, Rome, where he was appointed professor of mathematics in 1740. One of the first scientists of continental Europe to accept Isaac Newton’s gravitational theory, he published nearly 70 papers on optics, astronomy, gravitation, meteorology, and trigonometry.

A pioneer in geodesy, the science concerned with the size and shape of the Earth, he measured a meridian arc between Rome and Rimini, Italy, in 1750 in order to test his theory of the shape of the Earth. He accepted the chair of mathematics at the University of Pavia in 1764 and also served as director of the Brera Observatory in Milan. In 1769 he was invited to lead an expedition to California to observe a transit of Venus but the offer was rescinded because of Spanish bias against the Jesuits. When the Jesuits were suppressed in Italy in 1773, Boscovich accepted an invitation from King Louis XV of France to settle in Paris as director of optics for the navy. He returned to Italy in 1783.